DRAINAGE METHODS FOR COUNTY ROADS. 71 
in the foundation, struck off and shaped, it is not at all likely to be 
seriously defective in strength on account of the mixture having 
been too wet. The consistency necessary to meet this requirement 
frequently is described in specifications as " jellylike." 
The amount of water required to produce a jellylike consistency 
varies with the condition of the aggregates as well as with the 
amount of mixing a batch of concrete receives. In general, the better 
the concrete is mixed the less water is required, and the amount of 
water used for each batch should be just sufficient to produce the 
desired consistency when the batch has been mixed thoroughly. This 
amount can be best ascertained by trial, and frequently must be modi- 
fied from time to time as the work progresses. 
CONSTRUCTION. 
The different steps involved in constructing a concrete foundation 
should proceed in the following order: (1) The subgrade should be 
prepared in accordance with the method already described. (2) The 
materials should be hauled out and deposited on the subgrade. (3) 
The concrete should be mixed, placed, and properly finished. (4) 
The foundation should be kept closed to all traffic for about 10 days, 
and protected from too rapid drying out by a covering of earth or 
other suitable material. (5) The earth covering is removed and the 
foundation is ready to receive the pavement. 
Curbs are not mentioned above, because the order in which they 
are constructed depends on the type employed. If the curbs are sepa- 
rate from the foundation they should be constructed while the sub- 
grade is being prepared and before the foundation materials are 
hauled out. If constructed as flanges on the foundation, the outside 
forms should be set as the subgrade is prepared and then side forms 
while the concrete is being placed. Forms may consist of either 24- 
inch wooden boards or of steel channels, though the steel is to be pre- 
ferred. The forms should, of course, be set true to line and grade 
and should be well braced so as to resist springing out of shape 
when concrete is placed against them. 
The materials may be hauled out in any one of several different 
ways. From the standpoint of economy alone, teams ordinarily 
would be used for small quantities of work and moderately short 
hauls, tractors or motor trucks for good roads and long hauls, and 
industrial railways where the roads are poor and the quantity of 
work to be done is sufficient to warrant the purchase of the necessary 
equipment. From a standpoint of excellence, the industrial railway 
is preferable to the other, methods, because hauling over an 'industrial 
railway would not disturb the prepared subgrade in any way, while 
with the other methods it usually is impracticable to prevent the sub- 
